Actually they did, but Valve decided that the game scope is not enough for an episodic game, so they moved from episodic model game to a full sequel (Half-Life 3) in 2010s and again cancelled because they also developing Source 2 which at that time isn't finished yet. More info in this this article :
How in any way is this a refutation? Half-Life 2:Aftermath isn't a thing. It was a cancelled project. What does that have to do with how Episode 1 feels? Sure, they're connected in that it was supposed to be one single thing but the splitting up didn't cause that much of an issue.
Half-Life 2: Remastered Collection is a “Valve sanctioned” tune-up of their classic shooter. Alyx of paint. Craig Pearson. 2 years ago. 13.
Instead of a full-fledged sequel to Half-Life 2, Valve released Half-Life 2: Episode 1 in 2006, followed by Episode 2 a year later. These short games, each around four to six hours, were presented ap2Eo.